The Employment Non-Discrimination Act has been pending in Congress for two decades. Here is a look at the key turning points in the legislative history.

1994: ENDA was first introduced in the 103rd Congress in 1994 with 30 co-sponsors in the Senate and 137 co-sponsors in the House. The bill, though introduced in various forms since then and mainly supported by Democrats, has almost always had at least one Republican co-sponsor. Even in 1994, the proposal had the backing of Sen. Jim Jeffords, a Republican from Vermont who in 2001 became an independent who caucused with Democrats, as well as seven House Republicans.

1996: The Senate held a floor vote on ENDA but it failed by one vote, 50-49. The main sponsor, Sen. Edward M. Kennedy, D-Mass., gave an impassioned speech in the chamber, saying: “Today we have the chance to take a meaningful forward step on the road to make America America. We have a really important opportunity to turn our back on bigotry, to turn our back on intolerance, to turn our back on discrimination. We can take an important step in the progress of making America America.”

1998: President Bill Clinton, who had urged Congress in his State of the Union addresses to pass ENDA, signed an executive order that prohibited discrimination based on sexual orientation for federal employees.

2007: ENDA was introduced for the first time with language that protected gender identity. Though that specific provision was stripped from the bill when it came up for a vote in the House, it marked the first and only time that the proposal passed out of a chamber of Congress. The House supported the bill 235-184, but it eventually died in the Senate, mainly because President George W. Bush threatened a veto.

2013: The Senate Health, Education, Labor and Pensions Committee cleared ENDA on Wednesday, readying it for a vote by the full chamber. Majority Leader Harry Reid, D-Nev., said he plans to bring the legislation to the floor swiftly, and the bipartisan support the bill garnered in committee hints at the likelihood that it will pass the Senate.